The Navigator object contains properties that describe the
web browser in use. You can use its properties to perform
platform-specific customization. The name of this object
obviously refers to the Netscape Navigator browser, but
other browsers that implement JavaScript will support this
object as well.

There is only a single instance of the Navigator object,
which you can reference through the navigator
property of any Window object. Because of the implicit
window reference, you can always refer to the Navigator
object simply as navigator.